1. Technical Field
Exemplary embodiments relate generally to semiconductor memory devices, and more particularly to methods of reading data in nonvolatile memory devices and nonvolatile memory devices.
2. Discussion of the Related Art
Semiconductor memory devices may be typically classified into volatile semiconductor memory devices and nonvolatile semiconductor memory devices. Volatile semiconductor memory devices may perform read and write operations at a high speed, while contents stored therein may be lost when the devices are powered-off. Nonvolatile semiconductor memory devices may retain contents stored therein even when powered-off. For this reason, nonvolatile semiconductor memory devices may be used to store contents to be retained regardless of whether the devices are powered on or off.
Nonvolatile semiconductor memory devices may include a mask read-only memory (MROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), etc.
A flash memory device may be a typical nonvolatile memory device. A flash memory device may be widely used as the voice and image storing media of electronic apparatuses such as a computer, a cellular phone, a PDA, a digital camera, a camcorder, a voice recorder, an MP3 player, a handheld PC, a game machine, a facsimile, a scanner, a printer, etc.
In a read operation for a flash memory device, a threshold voltage distribution of memory cells connected to a particular word-line may shift by coupling from an adjacent word-line of the particular word-line. Therefore, it is desired to reduce the adjacent word-line coupling in a read operation of the flash memory device.